tough question
I can only tell you my son thinks it's worth it to him for this purpose racing and I think it isn't worth it to me for my purpose of coastal cruising. Here in New England, the worst thing we can run into (figuratively speaking) is fog for which it is obviously useless. If I were in the lighning capitol, I might have a different perspective. Depending on your definition of "offshore", my understanding is that coverage isn't available too far. You probably already know but if not, you can see a demo at most WM stores.